[PATCH RFC 09/77] ahci: Update MSI/MSI-X interrupts enablement code

Alexander Gordeev
2013-10-02T10:48:25Z

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
drivers/ata/ahci.c | 56 ++++++++++++++++++++++++++++++++-------------------
1 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 9d715ae..f1c8838 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1091,26 +1091,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
{}
#endif

-int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv)
+int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
+ struct ahci_host_priv *hpriv)
{
- int rc;
- unsigned int maxvec;
+ int rc, nvec;

- if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
- rc = pci_enable_msi_block_auto(pdev, &maxvec);
- if (rc > 0) {
- if ((rc == maxvec) || (rc == 1))
- return rc;
- /*
- * Assume that advantage of multipe MSIs is negated,
- * so fallback to single MSI mode to save resources
- */
- pci_disable_msi(pdev);
- if (!pci_enable_msi(pdev))
- return 1;
- }
- }
+ if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+ goto intx;
+
+ rc = pci_get_msi_cap(pdev);
+ if (rc < 0)
+ goto intx;
+
+ /*
+ * If number of MSIs is less than number of ports then Sharing Last
+ * Message mode could be enforced. In this case assume that advantage
+ * of multipe MSIs is negated and use single MSI mode instead.
+ */
+ if (rc < n_ports)
+ goto single_msi;
+
+ nvec = rc;
+ rc = pci_enable_msi_block(pdev, nvec);
+ if (rc)
+ goto intx;

+ return nvec;
+
+single_msi:
+ rc = pci_enable_msi(pdev);
+ if (rc)
+ goto intx;
+ return 1;
+
+intx:
pci_intx(pdev, 1);
return 0;
}
@@ -1277,10 +1291,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];

- n_msis = ahci_init_interrupts(pdev, hpriv);
- if (n_msis > 1)
- hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
/* save initial config */
ahci_pci_save_initial_config(pdev, hpriv);

@@ -1335,6 +1345,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
*/
n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));

+ n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
+ if (n_msis > 1)
+ hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
if (!host)
return -ENOMEM;
--
1.7.7.6